1. Field of the Invention
The present invention pertains to instruments and methods for use in endoscopic procedures and, more particularly, to an endoscopic portal providing a variable size passage to a surgical site within an anatomical cavity to prevent undesired fluid flow through the portal while allowing surgical instruments of various sizes to be selectively introduced through the portal and to permit expansion of the portal to facilitate removal of objects from and insertion of objects in the anatomical cavity as well as methods therefor.
2. Description of the Prior Art
Surgical procedures involving the placement of an endoscopic portal, such as a sleeve or cannula, through a wall of an anatomical cavity to provide a passage for insertion of surgical instruments into the cavity frequently require that the passage be sealed to prevent undesired flow of fluids through the endoscopic portal. For example, in many endoscopic medical procedures access to the interior of an anatomical cavity is gained by utilizing a surgical penetrating instrument, such as a trocar, obturator or needle, having a sharp penetrating point for penetrating a wall of the cavity to establish communication with the interior thereof. Upon penetration of the cavity wall by the penetrating instrument, a sleeve or cannula is left in place for utilization as a portal to introduce surgical instruments into the anatomical cavity. The surgical penetrating instrument is usually received within the sleeve, which passes through the wall of the anatomical cavity with the penetrating instrument and remains in situ after withdrawal of the penetrating instrument therefrom to provide a lumen establishing communication with a surgical site in the interior of the cavity. The sleeve typically has a proximal end disposed externally of the anatomical cavity and secured in a housing provided with a valve that allows the penetrating instrument to be inserted into and removed from the sleeve. Once the penetrating instrument has been removed from the sleeve, various instruments can be introduced into the anatomical cavity via the lumen of the sleeve dependent upon the operative procedure to be performed.
It is extremely important in endoscopic procedures to prevent undesired fluid flow to and from the surgical site; and, accordingly, the portal must be sealed prior to and subsequent to the introduction of surgical instruments and while such instruments are in place. In addition, fluids, such as gaseous phase carbon dioxide or nitrous oxide, may be introduced into the anatomical cavity for insufflation as part of the endoscopic procedure, and the escape of such fluids must be prevented during penetration of the cavity as well as during the operative procedure. The valves of endoscopic portals typically have a valve passage with a size corresponding to an outer diameter or size of the penetrating instrument to form a seal with the penetrating instrument, the size of the penetrating instrument varying in accordance with the endoscopic procedure being performed and the type of anatomical cavity being penetrated. Furthermore, the valves of endoscopic portals typically have been designed to close when the penetrating instrument is removed to prevent the flow of fluids through the valves. Many prior art endoscopic portals utilize a flapper or gate valve that is normally biased to a closed position and movable to an open position to allow the penetrating instrument to be inserted through the valve passage, which has a single, predetermined size corresponding to the size of the penetrating instrument. However, additional instruments to be introduced into the anatomical cavity through the valve passage may be of diverse types and sizes, and it will be appreciated that fluid can escape past smaller size instruments. Accordingly, such endoscopic portals suffer from the disadvantages of allowing the passage or leakage of fluids when surgical instruments smaller in size than the size of the single valve passage are introduced therethrough or of limiting the instruments to be introduced through the portal to a single size. Many attempts have been made to variably seal endoscopic portals to allow the introduction of various sized instruments therethrough; however, there still exists a great need for an endoscopic portal having a universal valve to prevent the escape of fluid from an anatomical cavity by sealing variably sized instruments passing through the portal without requiring placement in the portal of seals of various sizes.